Optimization of Ultrasonic—Assisted Extraction (UAE) Method Using Natural Deep Eutectic Solvent (NADES) to Increase Curcuminoid Yield from Curcuma longa L., Curcuma xanthorrhiza, and Curcuma mangga Val.

This study aims to optimize ultrasonic-assisted natural deep eutectic solvents (NADES) based extraction from C. longa. Choline chloride-lactic acid (CCLA-H2O = 1:1, b/v) was used to investigate the impact of various process parameters such as solvent’s water content, solid loading, temperature, and extraction time. The optimal yield of 79.635 mg/g of C. longa was achieved from extraction in 20% water content NADES with a 4% solid loading in 35 °C temperature for 1 h. Peleg’s model was used to describe the kinetics of the optimized ultrasonic-assisted extraction (UAE) method, and the results were found to be compatible with experimental data. The optimum conditions obtained from C. longa extraction were then used for the extraction of C. xanthorriza and C. mangga, which give yields of 2.056 and 31.322 mg/g, respectively. Furthermore, n-hexane was utilized as an anti-solvent in the separation process of curcuminoids extract from C. longa, C. xanthorriza, and C. mangga, which gave curcuminoid recovery of 39%, 0.74%, and 27%, respectively. Solidification of curcuminoids was also carried out using the crystallization method with n-hexane and isopropanol. However, the solution of CCLA and curcuminoids formed a homogeneous mixture with isopropanol. Hence, the curcuminoids could not be solidified due to the presence of NADES in the extract solution.

Curcuminoids are known for having many medical benefits. The pharmacological effects of curcuminoids, such as antiinflammation, antioxidant, antibacterial, anticancer, and antiallergy properties, have been medically proven, both in vitro and in vivo [4]. Curcumin is also known to inhibit angiogenesis and tumor development and to induce apoptosis [5,6]. In addition, based on in silico studies, curcumin is also known to have high affinity for the spike (s) glycoprotein of SARS-CoV-2 and ACE2 which indicates its potential antiviral activity in preventing the transmission of COVID-19 [7].
According to the Joint FAO/WHO Expert Committee, naturally extracted curcuminoids are preferred over chemically synthesized curcuminoids as a food additive. This has

Soxhlet Method
The Soxhlet method resulted in 88.476 mg curcuminoid/g from C. longa (8.8% w/w). The obtained yield was considered as reference, i.e., 100%. Note that the curcuminoid obtained from this experiment is a crude extract, since it is not pure and might still contain some other polyphenols and many other minor compounds. Viscous extract obtained from this process is 1.56 g (31.2% w/w) from the original 5 g C. longa powder.

Water Content (%) Variation
The major drawback of using NADES as an extraction solvent is its high viscosity which can inhibit the diffusion of the solvent to the cell matrix [12]. The dissolution of NADES with distilled water aims to reduce the high viscosity of NADES [15]. Therefore, in this study, the effect of adding water into NADES (20%, 25%, and 30%) was investigated.
The best variation obtained is 20% water content in NADES at 60 min with 43.83 mg/g curcuminoid extract yield. The other two variations, 25% and 30%, gave lower results at 60 min extraction time: 32.58 and 30.74 mg/g, respectively. The complete extraction data will be shown in Figure 1. As shown in Figure 1, the 20% water content in NADES gave the highest yield of curcuminoids. In ultrasonic extraction, viscosity and surface tension play a significant role [10]. The decrease in viscosity and surface tension causes the formation of cavitation explosions more easily. Fluids with lower viscosity tend to form stable bursts of bubbles and cavitation with a larger magnitude than those with high viscosity [19]. Thus, this helps facilitate easier diffusion of the solvent into the plant sample. However, adding water content of as much as 5% successively into NADES causes a decrease in the yield of curcuminoids. Gabriele (2019), who also investigated the effect of adding water content to NADES, stated that the hydrogen bond between HBA (hydrogen bond acceptor) and HBD (hydrogen bond donor) would weaken with the addition of water content up to 50% [20]. At 75% water content, the bond is completely broken. Therefore, in this experiment, 20% water content in NADES is the optimal condition.

Solid Loading (%) Variation
Mass transfer at the solid-liquid interface is influenced by the proportion of solids and the amount of solvent under specific extraction operating conditions. Therefore, in this study, the effect of % (w/v) solid loading (7%, 5%, and 4%) with extraction operating  As shown in Figure 1, the 20% water content in NADES gave the highest yield of curcuminoids. In ultrasonic extraction, viscosity and surface tension play a significant role [10]. The decrease in viscosity and surface tension causes the formation of cavitation explosions more easily. Fluids with lower viscosity tend to form stable bursts of bubbles and cavitation with a larger magnitude than those with high viscosity [19]. Thus, this helps facilitate easier diffusion of the solvent into the plant sample. However, adding water content of as much as 5% successively into NADES causes a decrease in the yield of curcuminoids. Gabriele (2019), who also investigated the effect of adding water content to NADES, stated that the hydrogen bond between HBA (hydrogen bond acceptor) and HBD (hydrogen bond donor) would weaken with the addition of water content up to 50% [20]. At 75% water content, the bond is completely broken. Therefore, in this experiment, 20% water content in NADES is the optimal condition.

Solid Loading (%) Variation
Mass transfer at the solid-liquid interface is influenced by the proportion of solids and the amount of solvent under specific extraction operating conditions. Therefore, in this study, the effect of % (w/v) solid loading (7%, 5%, and 4%) with extraction operating conditions of 20% water content in NADES, temperature 35 • C, particle size 0.25 mm, power 60% (6 s on, 4 s off), for 60 min was studied.
As shown in Figure 2, the best variation obtained is 4% solid loading at 60 min with 79.67 mg/g curcuminoid extract yield. The other two variations, 5% and 7%, gave lower results at 60 min extraction time: 64.55 and 43.83 mg/g, respectively.
As shown in Figure 2, the best variation obtained is 4% solid loading at 60 min with 79.67 mg/g curcuminoid extract yield. The other two variations, 5% and 7%, gave lower results at 60 min extraction time: 64.55 and 43.83 mg/g, respectively. The yield of curcuminoid extract increased alongside the decrease of solid loading. At a fixed amount of solid matrix, the more solvent volume used, the greater the concentration gradient between the plant cell matrix and the extraction medium. This increases the driving force to release curcuminoids from the sample matrix to the solvent. In addition, a decrease in the solids loading in the solvent also causes cavitation at a lower cavitation threshold [21]. This would significantly increase the extraction rate.

Temperature Variation
Based on Figure 3, the curcuminoids yield obtained increased alongside the increase in temperature from 35 °C to 55 °C. After 60 min of sonication, the maximum curcuminoids yield of 79.64, 80.64, and 84.27 mg/g was achieved from extraction temperatures of 35 °C, 45 °C, and 55 °C, respectively.   The yield of curcuminoid extract increased alongside the decrease of solid loading. At a fixed amount of solid matrix, the more solvent volume used, the greater the concentration gradient between the plant cell matrix and the extraction medium. This increases the driving force to release curcuminoids from the sample matrix to the solvent. In addition, a decrease in the solids loading in the solvent also causes cavitation at a lower cavitation threshold [21]. This would significantly increase the extraction rate.

Temperature Variation
Based on Figure 3, the curcuminoids yield obtained increased alongside the increase in temperature from 35 • C to 55 • C. After 60 min of sonication, the maximum curcuminoids yield of 79.64, 80.64, and 84.27 mg/g was achieved from extraction temperatures of 35 • C, 45 • C, and 55 • C, respectively.
As shown in Figure 2, the best variation obtained is 4% solid loading at 60 min with 79.67 mg/g curcuminoid extract yield. The other two variations, 5% and 7%, gave lower results at 60 min extraction time: 64.55 and 43.83 mg/g, respectively. The yield of curcuminoid extract increased alongside the decrease of solid loading. At a fixed amount of solid matrix, the more solvent volume used, the greater the concentration gradient between the plant cell matrix and the extraction medium. This increases the driving force to release curcuminoids from the sample matrix to the solvent. In addition, a decrease in the solids loading in the solvent also causes cavitation at a lower cavitation threshold [21]. This would significantly increase the extraction rate.

Temperature Variation
Based on Figure 3, the curcuminoids yield obtained increased alongside the increase in temperature from 35 °C to 55 °C. After 60 min of sonication, the maximum curcuminoids yield of 79.64, 80.64, and 84.27 mg/g was achieved from extraction temperatures of 35 °C, 45 °C, and 55 °C, respectively.   The yield of curcuminoid extract increases alongside the increase in temperature. Higher temperature increases the extraction rate because it gives the active compound more kinetic energy. According to diffusivity and solubility of solute, the temperature increase would increase both parameters and thus increase extraction effectivity [22]. Higher temperature would also increase solid material's pore size, increasing diffusivity further [10]. However, high temperatures can lead to curcumin degradation in the material. This happened at 55 • C temperature, at which the mixture color changed from bright yellow-orangish to dark brown. The dark brown color indicated other compounds, such as ferulic acid, vanillic acid, and vanillin [23,24]. Because of this, 55 • C temperature cannot be used as the optimal condition. Instead, the 35 • C temperature would be chosen since it gave a slightly lower result than the 45 • C and 55 • C, and it used less energy than both temperatures.

Effect of Extraction Time
The extraction process depends on reaction time, and in this study, the extraction process was also observed with variation in extraction time. The longer the extraction was carried out, the more yield was obtained. As shown in Figures 1-3, the extraction rate was very fast in the first 20 min. After that, the yields obtained increased gradually up to 1 h. The curcuminoid concentration gradient between the solvent and C. longa powder was extensive at the beginning of the extraction process. In addition, the extraction was facilitated by the ease of extraction from the outer matrix during the initial period. As time goes by, the concentration gradient is lower, and the extraction progress is slower because the remaining curcuminoids are in the core of the solid matrix, so this is influenced by diffusion from the solvent. Therefore, there is a limit on the curcuminoids that can be extracted. For every variation, an extraction capacity shows approximately how much curcuminoids can be extracted. The yield will not surpass the extraction capacity, no matter how long the extraction is carried out. The capacity can be calculated empirically using Peleg's model.

Optimized UAE and Soxhlet Method Comparison
The yield of curcuminoids obtained from the Soxhlet method is considered a value of 100%, which is 88.48 mg/g. In the extraction using the UAE method, a yield of 79.64 mg/g (90%) was obtained with the extraction process only at ±35 • C for 1 h. Figure 4 shows how the productivities obtained from extraction with Soxhlet and UAE compare. Although Soxhlet obtained a higher yield, it required a longer time, more solvent, and energy compared to the optimized UA method. Therefore, the productivity of the UAE method (79.64 mg/g·h) is better than that of Soxhlet (7.37 mg/g·h).
rial. This happened at 55 °C temperature, at which the mixture color changed from brigh yellow-orangish to dark brown. The dark brown color indicated other compounds, such as ferulic acid, vanillic acid, and vanillin [23,24]. Because of this, 55 °C temperature canno be used as the optimal condition. Instead, the 35 °C temperature would be chosen since i gave a slightly lower result than the 45 °C and 55 °C, and it used less energy than both temperatures.

Effect of Extraction Time
The extraction process depends on reaction time, and in this study, the extraction process was also observed with variation in extraction time. The longer the extraction wa carried out, the more yield was obtained. As shown in Figures 1-3, the extraction rate wa very fast in the first 20 min. After that, the yields obtained increased gradually up to 1 h The curcuminoid concentration gradient between the solvent and C. longa powder wa extensive at the beginning of the extraction process. In addition, the extraction was facili tated by the ease of extraction from the outer matrix during the initial period. As time goe by, the concentration gradient is lower, and the extraction progress is slower because th remaining curcuminoids are in the core of the solid matrix, so this is influenced by diffu sion from the solvent. Therefore, there is a limit on the curcuminoids that can be extracted For every variation, an extraction capacity shows approximately how much curcuminoid can be extracted. The yield will not surpass the extraction capacity, no matter how long the extraction is carried out. The capacity can be calculated empirically using Peleg' model.

Optimized UAE and Soxhlet Method Comparison
The yield of curcuminoids obtained from the Soxhlet method is considered a valu of 100%, which is 88.48 mg/g. In the extraction using the UAE method, a yield of 79.6 mg/g (90%) was obtained with the extraction process only at ±35 °C for 1 h. Figure 4 shows how the productivities obtained from extraction with Soxhlet and UAE compare. Although Soxhlet obtained a higher yield, it required a longer time, mor solvent, and energy compared to the optimized UA method. Therefore, the productivity of the UAE method (79.64 mg/g·h) is better than that of Soxhlet (7.37 mg/g·h).   The shear force generated due to cavitation along with the shock wave induces physical damage to the plant cell wall, thereby facilitating the release of the compound to be extracted [25]. Diffusion of the solvent also increases with swelling of the plant matrix and hydration by the solvent [26,27]. Ultrasonic wave also increases mass transfer, so solvent diffusion into the plant cell matrix is more effective [10]. Therefore, the UAE only takes a shorter time in the extraction process and requires less energy compared to Soxhlet.

Curcuminoid Extract from C. xanthorriza and C. mangga
The extraction of curcuminoids from C. xanthorriza and C. mangga with UAE was carried out using the optimized parameters previously obtained from C. longa extraction. Based on the experiment, the UAE-optimized method gave yields of 2.06 and 31.32 mg/g for C. xanthorriza and C. mangga, respectively. The comparison is shown on Figure 5.
The shear force generated due to cavitation along with the shock wave induces physical damage to the plant cell wall, thereby facilitating the release of the compound to be extracted [25]. Diffusion of the solvent also increases with swelling of the plant matrix and hydration by the solvent [26,27]. Ultrasonic wave also increases mass transfer, so solvent diffusion into the plant cell matrix is more effective [10]. Therefore, the UAE only takes a shorter time in the extraction process and requires less energy compared to Soxhlet.

Curcuminoid Extract from C. xanthorriza and C. mangga
The extraction of curcuminoids from C. xanthorriza and C. mangga with UAE was carried out using the optimized parameters previously obtained from C. longa extraction. Based on the experiment, the UAE-optimized method gave yields of 2.06 and 31.32 mg/g for C. xanthorriza and C. mangga, respectively. The comparison is shown on Figure 5. The yields obtained from C. xanthorriza and C. mangga were significantly lower than the one obtained from C. longa. C. xanthorriza has a curcuminoid content up to 1-2% of its total weight [2], while C. mangga has up to 3% [3]. C. longa has around 3-8% [1], which makes it the highest source of curcuminoid compared to the other two. C. xanthorriza does not contain bisdemethoxycurcumin [28], which is easier to extract compared to curcumin and desmethoxycurcumin [29]. This makes C. longa, which contains all three compounds, gave the highest yield. Therefore, C. longa is the best option to obtain curcuminoid extract.

Separation and Crystallization Methods
In optimal conditions, separation and crystallization methods were carried out on the curcuminoid extract obtained from C. longa, Javanese turmeric, and C. mangga. In this study, curcuminoids separated from oleoresin using the anti-solvent precipitation method, where n-hexane was used as antisolvent as curcuminoids are insoluble in it. This process gives curcuminoids recoveries of 39%, 0.74%, and 27% from C. longa, C. xanthorriza, and C. mangga, respectively.
The crystallization process is carried out after the separation process to obtain the curcuminoids in solid form. The mixture of isopropanol-hexane (1:1.5) at 40 °C was used in the solidification process. This process gave curcuminoids recoveries of 22%, 1.29%, and 13% from C. longa, C. xanthorriza, and C. mangga, respectively. However, curcuminoids extract cannot be solidified directly from NADES solution using isopropanol-hexane.
The result showed that both methods can recover some curcuminoids in the extract, which means both methods increase the concentration of curcuminoid extracted. The separation method resulted in a bigger recovery for C. longa, but the crystallization method had lower result. The opposite happened to C. xanthorriza and C. mangga, where the Turmeric Mango ginger Javanese turmeric The yields obtained from C. xanthorriza and C. mangga were significantly lower than the one obtained from C. longa. C. xanthorriza has a curcuminoid content up to 1-2% of its total weight [2], while C. mangga has up to 3% [3]. C. longa has around 3-8% [1], which makes it the highest source of curcuminoid compared to the other two. C. xanthorriza does not contain bisdemethoxycurcumin [28], which is easier to extract compared to curcumin and desmethoxycurcumin [29]. This makes C. longa, which contains all three compounds, gave the highest yield. Therefore, C. longa is the best option to obtain curcuminoid extract.

Separation and Crystallization Methods
In optimal conditions, separation and crystallization methods were carried out on the curcuminoid extract obtained from C. longa, Javanese turmeric, and C. mangga. In this study, curcuminoids separated from oleoresin using the anti-solvent precipitation method, where n-hexane was used as antisolvent as curcuminoids are insoluble in it. This process gives curcuminoids recoveries of 39%, 0.74%, and 27% from C. longa, C. xanthorriza, and C. mangga, respectively.
The crystallization process is carried out after the separation process to obtain the curcuminoids in solid form. The mixture of isopropanol-hexane (1:1.5) at 40 • C was used in the solidification process. This process gave curcuminoids recoveries of 22%, 1.29%, and 13% from C. longa, C. xanthorriza, and C. mangga, respectively. However, curcuminoids extract cannot be solidified directly from NADES solution using isopropanol-hexane.
The result showed that both methods can recover some curcuminoids in the extract, which means both methods increase the concentration of curcuminoid extracted. The separation method resulted in a bigger recovery for C. longa, but the crystallization method had lower result. The opposite happened to C. xanthorriza and C. mangga, where the curcuminoid recovery obtained from the crystallization method was bigger than that of the separation method.
The recovery of curcuminoid in the extract can be explained by the antisolvent used in the process. Curcuminoid extract was dissolved in n-hexane which acted as antisolvent. Difference of polarity caused the curcuminoid to precipitate at the bottom of the mixture while being separated from other impurities such as oleoresin [11].
The crystallization process then was attempted to solidify the extract and gain pure curcuminoid powder, but it was unsuccessful. The mixture between NADES and the antisolvent-solvent solution (n-hexane and isopropanol) caused a competition in which both solutions tried to dissolve the curcuminoid. This resulted in precipitation of curcuminoid extract, in which no solids were formed, but some curcuminoids could still be further recovered [11].

Kinetic Model
In this study, the extraction process is modeled with a semi-empirical kinetic model named Peleg's model. The simplified equation is shown below [12]. where: M t -final concentration of curcumin extract at time t (mg curcuminoid /g material ); M 0 -initial concentration of curcumin extract (mg curcuminoid /g material ); K 1 -Peleg's rate constant (min g material /mg curcuminoid ); K 2 -Peleg's capacity constant (g material /mg curcuminoid ); t-extraction time (min).
The equation is made into linear regression equation, with 1/M t as y, 1/t as x, K 1 as gradient, and K 2 as intercept. The equation is shown below.
The obtained data would be plotted on a graph to obtain the linear regression equation and coefficient of determination for the models. The model has some kinetic parameters, such as K 1 (Peleg's rate constant), K 2 (Peleg's capacity constant), B 0 (initial extraction rate), and C e (curcuminoids concentration at equilibrium) [30]. Peleg's model was used to describe the extraction kinetic of the optimized UAE method. C. longa extraction results are used to make this model. Each variation would have one Peleg's model to determine their own parameters. The Peleg's models created from three variations are shown in Figures 6-8. extract, in which no solids were formed, but some curcuminoids could still b covered [11].

Kinetic Model
In this study, the extraction process is modeled with a semi-empirical k named Peleg's model. The simplified equation is shown below [12].
The equation is made into linear regression equation, with 1/Mt as y, 1 gradient, and K2 as intercept. The equation is shown below.
The obtained data would be plotted on a graph to obtain the linear regr tion and coefficient of determination for the models. The model has some ki eters, such as K1 (Peleg's rate constant), K2 (Peleg's capacity constant), B0 (init rate), and Ce (curcuminoids concentration at equilibrium) [30]. Peleg's model was used to describe the extraction kinetic of the opt method. C. longa extraction results are used to make this model. Each vari have one Peleg's model to determine their own parameters. The Peleg's mo from three variations are shown in Figures 6-8.   Compatibility of kinetics study with experiment data was determined adjusted R 2 , and E (%) value. Table 1 revealed the results obtained for Peleg'   Compatibility of kinetics study with experiment data was determined adjusted R 2 , and E (%) value.  Compatibility of kinetics study with experiment data was determined using RMSE, adjusted R 2 , and E (%) value. Table 1 revealed the results obtained for Peleg's model.  Table 2 shows the kinetic parameters for Peleg's model, which include K 1 (Peleg's rate constant), K 2 (Peleg's capacity constant), B 0 (initial extraction rate), and C e (curcuminoids concentration at equilibrium). The Peleg's model showed a relation between extraction time and the extract concentration in solvent. Figures 6-8 showed an increase of curcuminoid extract yield alongside the increase of extraction time. The errors in these models are very miniscule and can be ignored. The model showed a very good coefficient of determination (R 2 ), which means a good correlation between each data. The parameters shown can illustrate how well the extraction of each variations went. The bigger the C e , more curcuminoid extract can be obtained from the variation that is being carried out. Since this model is linear, it showed that the 55 • C variation has the highest C e . However, this is not the case since the 55 • C variation has a risk of curcumin degradation because of high temperature, indicated by color change of the mixture from yellow-orangish to dark brown. While the model showed a good correlation with the experimental data, it cannot show how the extraction went in the experiment. That is why the optimal variation is the 35 • C temperature.

Materials
Fresh C. longa was purchased at Tangerang (Banten, Indonesia) local market. Fresh C. mangga was commercially purchased from a local business at Garut (West Java, Indonesia). Fresh C. xanthorriza was purchased at local market in Jakarta Selatan (DKI Jakarta, Indonesia).

Preparation of NADES
In this study, NADES was prepared with the heating and stirring method. Choline chloride (HBA) and lactic acid (HBD) were mixed with a 1:2 molar ratio. Water content in NADES was adjusted by adding aquadest. The components were mixed in a beaker glass at 70 • C with constant stirring until clear, homogenous liquid formed. NADES was then stored in a sealed glass at room temperature until use.

Soxhlet Extraction
Soxhlet extraction was utilized as the reference method to compare the optimization results performed on the ultrasound-assisted extraction (UAE) method. The procedure for this method was carried out based on Patil et al. (2020) [12]. A total of 5 g of C. longa powder in the thimble was extracted using ethanol (96%) with a ratio of 1:50 (w/v). The extraction process was carried out for 12 h at temperature of ±70 • C. The curcuminoid yield obtained was a reference result (100%).

Ultrasonic-Assisted Extraction
Ultrasound-Assisted Extraction was carried out with a NADES-based solvent, choline chloride: lactic acid (1:2), with 250 W rated output power and a frequency of 22 kHz. The extraction was performed with a sonicator probe operated at pulsed mode with a 60% duty cycle (6 s on and 4 s off). The ultrasonic waves were transmitted directly to the mixture for 1 h, with data collection every 10 min. The samples then were diluted, centrifuged, and analyzed quantitatively using UV-VIS spectrophotometry. The effect of water content (%) in NADES, solid loading, extraction temperature, and time were investigated to optimize the process.

Curcumin Quantification
Spectrophotometry UV-VIS was used to analyze the curcuminoids concentration from the samples. The measurements were carried out at a wavelength of 415 nm, giving the absorbance data. The concentrations of curcuminoids (ppm) were calculated using a standard curve of 95% pure curcuminoids and consequently calculated as the yield of curcuminoids (mg/g).

Curcumin Extract Separation
In the present work, curcuminoids and oleoresin were separated using an antisolvent technique with n-hexane. The viscous extract obtained from the optimized UAE method was centrifuged at 6000 rpm for 50 min, and the supernatant was stored in another tube. A known volume of supernatant was mixed with hexane (1:25, v/v) and allowed to stand for 24 h. After 24 h, the solution was stirred with a magnetic stirrer at 600 rpm for 3 h. The precipitated mixture was separated from oleoresin by centrifuging the solution at 1000 rpm for 10 min. The recovery of curcuminoids was analyzed quantitatively using spectrophotometry UV-VIS at 415 nm wavelength.

Curcumin Extract Crystallization
The separated curcuminoids from a previous process were further purified employing the crystallization method used by Pawar et al. (2018) [8]. Curcuminoid extract was added to 10 mL of isopropanol and n-hexane mixture (4:6, v/v) at 40 • C. The mixture and extract were then cooled in a freezer (temperature below 10 • C) for approximately 1 h. The sediment then was separated from the filtrate using a vacuum filter and then analyzed using UV-VIS spectrophotometry.

Conclusions
The optimal condition for NADES based UAE in this research is 20% water content, 4% solid loading, 35 • C temperature, and 60 min extraction time. This condition resulted in 79.636 mg curcuminoid extract/g C. longa. Peleg's model was used to describe the kinetics of the optimized UAE method, and the results were found to be compatible with experimental data. Based on the yield obtained, the use of solvents, temperature, and extraction time, the optimized UAE method can be chosen as an alternative to the Soxhlet method. Furthermore, C. longa is the best material from which to obtain curcumin extract, since C. xanthorriza and C. mangga gave a significantly lower result. The separation and crystallization methods are worth carrying out with C. longa extract since this extract gave the highest recoveries of curcuminoid, which were 39% from separation and 22% from crystallization. However, curcuminoids could not be solidified due to the presence of NADES in the extract solution.